H/t AVI, from Michael Novak a few years ago: Christmas Atheists.
Many forms of atheism, and plenty of atheists appear to attend church or synagogue for all sorts of reasons - including the hope that faith might be contagious. One quote from Novak's post:
Some years ago I read a book on atheism, by a devout atheist (if that is the right word), who had found to his surprise that a large majority of those Americans who call themselves atheists actually believe in some more-than-human power, force, intelligence in all things. This is a position not altogether unlike the ancients (and the moderns) described in #3 above. The ancients did not call such persons atheists, but held them to be theists, albeit under a vague and unclear sort of deity, but intelligent and powerful and drawing all things toward the good.
"Higher Power"? That is certainly a form of theism albeit undeveloped.